Tuberculosis (TB) is a bacterial disease caused by various strains of mycobacteria, such as Mycobacterium tuberculosis (MTB) most often found in the lungs. It is transmitted from person to person through the air when individuals with pulmonary or laryngeal tuberculosis, cough, sneeze, or spit, and propel MTB into the air. It is estimated that one-third of the world population is infected with MTB and 9 million people develop TB each year. TB continues to be a leading cause of human infectious disease and drug-resistant strains of MTB are on the rise, especially in developing countries.
Two common first-line drugs for the treatment of MTB include isoniazid (INH) and rifampicin (RIF), and patients can acquire drug resistant MTB from living in or visiting a place where drug resistance is prevalent. Patients can also develop drug resistant MTB when their antibiotic treatment regimen is interrupted. Culturing on solid or liquid media is still considered the gold standard for MTB and MTB drug resistance detection, but culturing can take up to eight weeks for results. Many commercial nucleic acid tests for MTB drug resistance have a very fast turn-around time, but cannot detect a population with a small percentage of mutant species in a mixed infection containing both wild type and mutant species. Thus there is a need in the art for a quick and reliable method to specifically detect MTB resistant to rifampicin (MTB-RIF) and/or MTB resistant to isoniazid (MTB-INH) in a sensitive manner.